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1.
Cell Tissue Res ; 395(1): 39-51, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37982872

RESUMO

The pig is an important translational model for studying intestinal physiology and disorders for its many homologies with humans, including the organization of the enteric nervous system (ENS), the major regulator of gastrointestinal functions. This study focused on the quantification and neurochemical characterization of substance P (SP) neurons in the pig ascending (AC) and descending colon (DC) in wholemount preparations of the inner submucosal plexus (ISP), outer submucosal plexus (OSP), and myenteric plexus (MP). We used antibodies for the pan-neuronal marker HuCD, and choline acetyltransferase (ChAT) and neuronal nitric oxide synthase (nNOS), markers for excitatory and inhibitory transmitters, for multiple labeling immunofluorescence and high-resolution confocal microscopy. The highest density of SP immunoreactive (IR) neurons was in the ISP (222/mm2 in the AC, 166/mm2 in the DC), where they make up about a third of HuCD-IR neurons, compared to the OSP and MP (19-22% and 13-17%, respectively, P < 0.001-0.0001). HuCD/SP/ChAT-IR neurons (up to 23%) were overall more abundant than HuCD/SP/nNOS-IR neurons (< 10%). Most SP-IR neurons contained ChAT-IR (62-85%), whereas 18-38% contained nNOS-IR with the highest peak in the OSP. A subpopulation of SP-IR neurons contains both ChAT- and nNOS-IR with the highest peak in the OSP and ISP of DC (33-36%) and the lowest in the ISP of AC (< 10%, P < 0.001). SP-IR varicose fibers were abundant in the ganglia. This study shows that SP-IR neurons are functionally distinct with variable proportions in different plexuses in the AC and DC reflecting diverse functions of specific colonic regions.


Assuntos
Plexo Mientérico , Plexo Submucoso , Humanos , Suínos , Animais , Substância P , Neurônios , Colo , Colina O-Acetiltransferase
2.
Cell Tissue Res ; 383(2): 645-654, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32965550

RESUMO

The enteric nervous system (ENS) controls gastrointestinal functions. In large mammals' intestine, it comprises an inner (ISP) and outer (OSP) submucous plexus and a myenteric plexus (MP). This study quantifies enteric neurons in the ISP, OSP, and MP of the pig ascending (AC) and descending colon (DC) using the HuC/D, choline acetyltransferase (ChAT), and neuronal nitric oxide synthase (nNOS) neuronal markers in whole mount preparations with multiple labeling immunofluorescence. We established that the ISP contains the highest number of HuC/D neurons/mm2, which were more abundant in AC vs. DC, followed by OSP and MP with similar density in AC and DC. In the ISP, the density of ChAT immunoreactive (IR) neurons was very similar in AC and DC (31% and 35%), nNOS-IR neurons were less abundant in AC than DC (15% vs. 42%, P < 0.001), and ChAT/nNOS-IR neurons were 5% and 10%, respectively. In the OSP, 39-44% of neurons were ChAT-IR in AC and DC, while 45% and 38% were nNOS-IR and 10-12% were ChAT/nNOS-IR (AC vs. DC P < 0.05). In the MP, ChAT-IR neurons were 44% in AC and 54% in DC (P < 0.05), nNOS-IR neurons were 50% in both, and ChAT/nNOS-IR neurons were 12 and 18%, respectively. The ENS architecture with multilayered submucosal plexuses and the distribution of functionally distinct groups of neurons in the pig colon are similar to humans, supporting the suitability of the pig as a model and providing the platform for investigating the mechanisms underlying human colonic diseases.


Assuntos
Colina O-Acetiltransferase/imunologia , Colo/inervação , Sistema Nervoso Entérico/citologia , Plexo Mientérico/citologia , Neurônios/enzimologia , Óxido Nítrico Sintase/imunologia , Plexo Submucoso/citologia , Animais , Contagem de Células , Masculino , Suínos , Porco Miniatura
3.
Am J Physiol Regul Integr Comp Physiol ; 313(4): R473-R486, 2017 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-28724546

RESUMO

High-protein diet (HPD) curtails obesity and/or fat mass, but it is unknown whether it reverses neuroinflammation or alters glucose levels, CCK sensitivity, and gut microbiome in rats fed a Western diet (WD)-induced obesity (DIO). Male rats fed a WD (high fat and sugar) for 12 wk were switched to a HPD for 6 wk. Body composition, food intake, meal pattern, sensitivity to intraperitoneal CCK-8S, blood glucose, brain signaling, and cecal microbiota were assessed. When compared with a normal diet, WD increased body weight (9.3%) and fat mass (73.4%). CCK-8S (1.8 or 5.2 nmol/kg) did not alter food intake and meal pattern in DIO rats. Switching to a HPD for 6 wk reduced fat mass (15.7%) with a nonsignificantly reduced body weight gain, normalized blood glucose, and decreased feeding after CCK-8S. DIO rats on the WD or switched to a HPD showed comparable microbial diversity. However, in HPD versus WD rats, there was enrichment of 114 operational taxonomic units (OTUs) and depletion of 188 OTUs. Of those, Akkermansia muciniphila (enriched on a HPD), an unclassified Clostridiales, a member of the RF39 order, and a Phascolarctobacterium were significantly associated with fat mass. The WD increased cytokine expression in the hypothalamus and dorsal medulla that was unchanged by switching to HPD. These data indicate that HPD reduces body fat and restores glucose homeostasis and CCK sensitivity, while not modifying brain inflammation. In addition, expansion of cecal Akkermansia muciniphila correlated to fat mass loss may represent a potential peripheral mechanism of HPD beneficial effects.


Assuntos
Encéfalo/efeitos dos fármacos , Ceco/efeitos dos fármacos , Colecistocinina/farmacologia , Proteínas Alimentares/farmacologia , Encefalite/metabolismo , Microbiota/efeitos dos fármacos , Obesidade/microbiologia , Animais , Glicemia/metabolismo , Composição Corporal/efeitos dos fármacos , Peso Corporal/efeitos dos fármacos , Encéfalo/metabolismo , Ceco/metabolismo , Ceco/microbiologia , Citocinas/metabolismo , Dieta Ocidental , Ingestão de Alimentos/efeitos dos fármacos , Masculino , Obesidade/metabolismo , Ratos , Ratos Sprague-Dawley
4.
Dig Dis Sci ; 60(4): 858-67, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25701320

RESUMO

BACKGROUND: Corticotropin-releasing factor (CRF) peptides exert profound effects on the secretomotor function of the gastrointestinal tract. Nevertheless, despite the presence of CRF peptides and receptors in colonic tissue, their influence on colonic blood flow (CBF) is unknown. AIM: To determine the effect and mechanism of members of the CRF peptide family on CBF in isoflurane-anesthetized rats. METHODS: Proximal CBF was measured with laser-Doppler flowmetry simultaneously with mean arterial blood pressure (MABP) measurement. Rats were injected with intravenous human/rat CRF (CRF1 > CRF2 affinity), mouse urocortin 2 (mUcn2, selective CRF2 agonist), or sauvagine (SVG, CRF2 > CRF1 affinity) at 1-30 µg/kg. The nitric oxide (NO) synthase inhibitor, L-NAME (3 mg/kg, iv), the cyclooxygenase inhibitor, indomethacin (Indo, 5 mg/kg, ip), or selective CRF2 antagonist, astressin2-B (Ast2B, 50 µg/kg, iv) was given before SVG injection (10 µg/kg, iv). RESULTS: SVG and mUcn2 dose-dependently increased CBF while decreasing MABP and colonic vascular resistance (CVR). CRF had no effect on CBF, but increased CVR. The hyperemic effect of SVG was inhibited by L-NAME but not by Indo, whereas hypotension was partially reduced by L-NAME. Sensory denervation had no effect on SVG-induced changes. Ast2B inhibited SVG-induced hyperemia and decreased CVR, and partially reduced the hypotension. CONCLUSIONS: Peripheral CRF2 activation induces colonic hyperemia through NO synthesis, without involving prostaglandin synthesis or sensory nerve activation, suggesting a direct action on the endothelium and myenteric neurons. Members of the CRF peptide family may protect the colonic mucosa via the activation of the CRF2 receptor.


Assuntos
Colo/irrigação sanguínea , Hormônio Liberador da Corticotropina/metabolismo , Óxido Nítrico/metabolismo , Receptores de Hormônio Liberador da Corticotropina/metabolismo , Animais , Pressão Sanguínea , Capsaicina , Hormônio Liberador da Corticotropina/agonistas , Hiperemia/metabolismo , Masculino , NG-Nitroarginina Metil Éster , Ratos Sprague-Dawley , Receptores de Hormônio Liberador da Corticotropina/antagonistas & inibidores , Circulação Esplâncnica , Resistência Vascular
5.
Gastroenterology ; 144(5): 967-77, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23380084

RESUMO

BACKGROUND & AIMS: Diet has major effects on the intestinal microbiota, but the exact mechanisms that alter complex microbial communities have been difficult to elucidate. In addition to the direct influence that diet exerts on microbes, changes in microbiota composition and function can alter host functions such as gastrointestinal (GI) transit time, which in turn can further affect the microbiota. METHODS: We investigated the relationships among diet, GI motility, and the intestinal microbiota using mice that are germ-free (GF) or humanized (ex-GF mice colonized with human fecal microbiota). RESULTS: Analysis of gut motility revealed that humanized mice fed a standard polysaccharide-rich diet had faster GI transit and increased colonic contractility compared with GF mice. Humanized mice with faster transit due to administration of polyethylene glycol or a nonfermentable cellulose-based diet had similar changes in gut microbiota composition, indicating that diet can modify GI transit, which then affects the composition of the microbial community. However, altered transit in mice fed a diet of fermentable fructooligosaccharide indicates that diet can change gut microbial function, which can affect GI transit. CONCLUSIONS: Based on studies in humanized mice, diet can affect GI transit through microbiota-dependent or microbiota-independent pathways, depending on the type of dietary change. The effect of the microbiota on transit largely depends on the amount and type (fermentable vs nonfermentable) of polysaccharides present in the diet. These results have implications for disorders that affect GI transit and gut microbial communities, including irritable bowel syndrome and inflammatory bowel disease.


Assuntos
Bactérias/genética , DNA Bacteriano/análise , Dieta , Metabolismo Energético , Trato Gastrointestinal/microbiologia , Trânsito Gastrointestinal/fisiologia , Vida Livre de Germes , Metagenoma , Animais , Trato Gastrointestinal/metabolismo , Camundongos
6.
Neurogastroenterol Motil ; : e14927, 2024 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-39344695

RESUMO

BACKGROUND AND AIMS: The endocannabinoid (eCB) system includes ligands (anandamide and 2-arachidonoyl glycerol, 2-AG), receptors and catabolizing enzymes (fatty acid amide hydrolase, FAAH and monoacylglycerol lipase) expressed in both the brain and gut. We investigated whether the FAAH inhibitor, URB597, influenced visceral pain to colorectal distension (CRD) in an acute stress-related model of visceral hypersensitivity induced by the selective corticotropin-releasing factor receptor subtype 1 (CRF1) agonist, cortagine. METHODS: Male Sprague-Dawley rats were injected subcutaneously (SC) with URB597 (3 mg/kg) or vehicle and 2 h later, intraperitoneally with cortagine (10 µg/kg) or vehicle. The visceromotor responses (VMR) were assessed to a first CRD (baseline) before injections, and to a second CRD 15 min after the last treatment. Brain, jejunum, and proximal colon were collected from treated and naïve rats for levels quantification of three fatty acid amides (FAAs) [anandamide (arachidonyl-ethanolamide, AEA), oleoyl-ethanolamide (OEA) and palmitoyl-ethanolamide (PEA)], and 2-AG. In separate animals, defecation/diarrhea were monitored after URB597 and cortagine. KEY RESULTS: URB597 inhibited cortagine-induced increased VMR at 40 mmHg (89.0 ± 14.8% vs. 132.5 ± 15.6% for vehicle SC, p < 0.05) and 60 mmHg (107.5 ± 16.1% vs. 176.9 ± 24.4% for vehicle SC, p < 0.001) while not influencing basal VMR. In URB597 plus cortagine group, FAAs levels increased in the brain and intestinal tissue while 2-AG did not change. URB597 did not modify cortagine-induced defecation/diarrhea versus vehicle. CONCLUSIONS AND INFERENCES: URB597 shows efficacy to elevate brain and intestinal FAAs and to counteract the colonic hypersensitivity induced by peripheral activation of CRF1 signaling supporting a potential strategy of FAAH inhibitors to alleviate stress-related visceral hypersensitivity.

7.
Front Neurosci ; 17: 1204233, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37650102

RESUMO

Introduction: The central and peripheral nervous systems provide cholinergic innervation in the colon. The ability to assess their neuroanatomical distinctions is still a challenge. The pig is regarded as a relevant translational model due to the close similarity of its enteric nervous system (ENS) with that of human. Opioid-induced constipation is one of the most common side effects of opioid therapy. Methods: We developed an approach to differentiate the central and peripheral cholinergic innervation of the pig colon using double immunolabeling with a novel mouse anti-human peripheral type of choline acetyltransferase (hpChAT) antibody combined with a rabbit anti-common type of ChAT (cChAT) antibody, a reliable marker of cholinergic neurons in the central nervous system. We examined their spatial configurations in 3D images of the ENS generated from CLARITY-cleared colonic segments. The density was quantitated computationally using Imaris 9.7. We assessed changes in the distal colon induced by daily oral treatment for 4 weeks with the µ opioid receptor agonist, loperamide (0.4 or 3 mg/kg). Results: The double labeling showed strong cChAT immunoreactive (ir) fibers in the cervical vagus nerve and neuronal somata and fibers in the ventral horn of the sacral (S2) cord while hpChAT immunoreactivity was visualized only in the ENS but not in the vagus or sacral neural structures indicating the selectivity of these two antibodies. In the colonic myenteric plexus, dense hpChAT-ir neurons and fibers and varicose cChAT-ir fibers surrounding hpChAT-ir neurons were simultaneously visualized in 3D. The density of cChAT-ir varicose fibers in the outer submucosal plexus of both males and females were higher in the transverse and distal colon than in the proximal colon and in the myenteric plexus compared to the outer submucosal plexus and there was no cChAT innervation in the inner submucosal plexus. The density of hpChAT in the ENS showed no segmental or plexus differences in both sexes. Loperamide at the highest dose significantly decreased the density hpChAT-ir fibers + somata in the myenteric plexus of the distal colon. Discussion: These data showed the distinct density of central cholinergic innervation between myenteric and submucosal plexuses among colonic segments and the localization of cChAT-ir fibers around peripheral hpChAT neurons in 3D. The reduction of cholinergic myenteric innervation by chronic opiate treatment points to target altered prokinetic cholinergic pathway to counteract opiate constipation.

8.
Commun Biol ; 6(1): 98, 2023 01 24.
Artigo em Inglês | MEDLINE | ID: mdl-36693960

RESUMO

The porcine gut is increasingly regarded as a useful translational model. The enteric nervous system in the colon coordinates diverse functions. However, knowledge of the molecular profiling of porcine enteric nerve system and its similarity to that of human is still lacking. We identified the distinct transcriptional programs associated with functional characteristics between inner submucosal and myenteric ganglia in porcine proximal and distal colon using bulk RNA and single-cell RNA sequencing. Comparative transcriptomics of myenteric ganglia in corresponding colonic regions of pig and human revealed highly conserved programs in porcine proximal and distal colon, which explained >96% of their transcriptomic responses to vagal nerve stimulation, suggesting that porcine proximal and distal colon could serve as predictors in translational studies. The conserved programs specific for inflammatory modulation were displayed in pigs with vagal nerve stimulation. This study provides a valuable transcriptomic resource for understanding of human colonic functions and neuromodulation using porcine model.


Assuntos
Sistema Nervoso Entérico , Transcriptoma , Humanos , Animais , Suínos , Colo/inervação
9.
IEEE Trans Biomed Circuits Syst ; 17(5): 941-951, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37363840

RESUMO

Monitoring of colon activity is currently limited to tethered systems like anorectal manometry. These systems have significant drawbacks, but fundamentally limit the observation time of colon activity, reducing the likelihood of detecting specific clinical events. While significant technological advancement has been directed to mobile sensor capsules, this work describes the development and feasibility of a stationary sensor for describing the coordinated activity between neighboring segments of the colon. Unlike wireless capsules, this device remains in position and measures propagating pressure waves and impedances between colon segments to describe activity and motility. This low-power, flexible, wireless sensor-the colon monitor to capture activity (ColoMOCA) was validated in situ and in vivo over seven days of implantation. The ColoMOCA diameter was similar to common endoscopes to allow for minimally invasive diagnostic placement. The ColoMOCA included two pressure sensors, and three impedance-sensing electrodes arranged to describe the differential pressures and motility between adjacent colon segments. To prevent damage after placement in the colon, the ColoMOCA was fabricated with a flexible polyimide circuit board and a silicone rubber housing. The resulting device was highly flexible and suitable for surgical attachment to the colon wall. In vivo testing performed in eleven animals demonstrated suitability of both short term (less than 3 hours) and 7-day implantations. Data collected wirelessly from animal experiments demonstrated the ColoMOCA described colon activity similarly to wired catheters and allowed untethered, conscious monitoring of organ behavior.


Assuntos
Colo , Próteses e Implantes , Animais , Eletrodos , Impedância Elétrica , Catéteres
10.
Gastroenterology ; 140(5): 1586-96.e6, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21277852

RESUMO

BACKGROUND & AIMS: Corticotropin-releasing factor receptor-1 (CRF(1)) mediates the stress-induced colonic motor activity. Less is known about the role of CRF(2) in the colonic response to stress. METHODS: We studied colonic contractile activity in rats and CRF(2)-/-, CRF-overexpressing, and wild-type mice using still manometry; we analyzed defecation induced by acute partial-restraint stress (PRS), and/or intraperitoneal injection of CRF ligands. In rats, we monitored activation of the colonic longitudinal muscle myenteric plexus (LMMP) neurons and localization of CRF(1) and CRF(2) using immunohistochemical and immunoblot analyses. We measured phosphorylation of extracellular signal-regulated kinase 1/2 by CRF ligands in primary cultures of LMMP neurons (PC-LMMPn) and cyclic adenosine monophosphate (cAMP) production in human embryonic kidney-293 cells transfected with CRF(1) and/or CRF(2). RESULTS: In rats, a selective agonist of CRF(2) (urocortin 2) reduced CRF-induced defecation (>50%), colonic contractile activity, and Fos expression in the colonic LMMP. A selective antagonist of CRF(2) (astressin(2)-B) increased these responses. Urocortin 2 reduced PRS-induced colonic contractile activity in wild-type and CRF-overexpressing mice, whereas disruption of CRF(2) increased PRS-induced colonic contractile activity and CRF-induced defecation. CRF(2) colocalized with CRF(1) and neuronal nitric oxide synthase in the rat colon, LMMP, and PC-LMMPn. CRF-induced phosphorylation of extracellular signal-regulated kinase in PC-LMMPn; this was inhibited or increased by a selective antagonist of CRF(1) (NBI35965) or astressin(2)-B, respectively. The half maximal effective concentration, EC(50), for the CRF-induced cAMP response was 8.6 nmol/L in human embryonic kidney-293 cells that express only CRF(1); this response was suppressed 10-fold in cells that express CRF(1) and CRF(2). CONCLUSIONS: In colon tissues of rodents, CRF(2) activation inhibits CRF(1) signaling in myenteric neurons and the stress-induced colonic motor responses. Disruption of CRF(2) function impairs colonic coping responses to stress.


Assuntos
Colo/fisiopatologia , Motilidade Gastrointestinal/fisiologia , Plexo Mientérico/metabolismo , Receptores de Hormônio Liberador da Corticotropina/metabolismo , Estresse Fisiológico , Doença Aguda , Animais , Colo/metabolismo , Colo/patologia , Modelos Animais de Doenças , Feminino , Motilidade Gastrointestinal/efeitos dos fármacos , Humanos , Imuno-Histoquímica , Injeções Intraperitoneais , Masculino , Camundongos , Camundongos Endogâmicos , Plexo Mientérico/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Receptores de Hormônio Liberador da Corticotropina/efeitos dos fármacos , Urocortinas/administração & dosagem
12.
Am J Physiol Gastrointest Liver Physiol ; 298(1): G45-56, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19892938

RESUMO

Peptide YY (PYY) antisecretory effect on intestinal epithelia is well established, whereas less is known about its actions to influence colonic motility in conscious animals. We characterized changes in basal function and stimulated colonic motor function induced by PYY-related peptides in conscious mice. PYY(3-36), PYY, and neuropeptide Y (NPY) (8 nmol/kg) injected intraperitoneally inhibited fecal pellet output (FPO) per hour during novel environment stress by 90%, 63%, and 57%, respectively, whereas the Y(1)-preferring agonists, [Pro(34)]PYY and [Leu(31),Pro(34)]NPY, had no effect. Corticotrophin-releasing factor 2 receptor antagonist did not alter PYY(3-36) inhibitory action. PYY and PYY(3-36) significantly reduced restraint-stimulated defecation, and PYY(3-36) inhibited high-amplitude distal colonic contractions in restrained conscious mice for 1 h, by intraluminal pressure with the use of a microtransducer. PYY suppression of intraperitoneal 5-hydroxytryptophan induced FPO and diarrhea was blocked by the Y(2) antagonist, BIIE0246, injected intraperitoneally and mimicked by PYY(3-36), but not [Leu(31),Pro(34)]NPY. PYY(3-36) also inhibited bethanechol-stimulated FPO and diarrhea. PYY(3-36) inhibited basal FPO during nocturnal feeding period and light phase in fasted/refed mice for 2-3 h, whereas the reduction of food intake lasted for only 1 h. PYY(3-36) delayed gastric emptying after fasting-refeeding by 48% and distal colonic transit time by 104%, whereas [Leu(31),Pro(34)]NPY had no effect. In the proximal and distal colon, higher Y(2) mRNA expression was detected in the mucosa than in muscle layers, and Y(2) immunoreactivity was located in nerve terminals around myenteric neurons. These data established that PYY/PYY(3-36) potently inhibits basal and stress/serotonin/cholinergic-stimulated propulsive colonic motor function in conscious mice, likely via Y(2) receptors.


Assuntos
Colo/fisiologia , Diarreia/fisiopatologia , Motilidade Gastrointestinal/fisiologia , Peptídeo YY/metabolismo , Receptores de Neuropeptídeo Y/metabolismo , 5-Hidroxitriptofano/metabolismo , 5-Hidroxitriptofano/farmacologia , Doença Aguda , Animais , Arginina/análogos & derivados , Arginina/farmacologia , Benzazepinas/farmacologia , Betanecol/farmacologia , Colo/efeitos dos fármacos , Colo/inervação , Estado de Consciência , Diarreia/induzido quimicamente , Diarreia/tratamento farmacológico , Ingestão de Alimentos/efeitos dos fármacos , Ingestão de Alimentos/fisiologia , Vias Eferentes/efeitos dos fármacos , Vias Eferentes/fisiologia , Esvaziamento Gástrico/efeitos dos fármacos , Esvaziamento Gástrico/fisiologia , Motilidade Gastrointestinal/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Plexo Mientérico/efeitos dos fármacos , Plexo Mientérico/fisiologia , Neuropeptídeo Y/análogos & derivados , Neuropeptídeo Y/antagonistas & inibidores , Neuropeptídeo Y/metabolismo , Neuropeptídeo Y/farmacologia , Parassimpatomiméticos/farmacologia , Fragmentos de Peptídeos , Peptídeo YY/farmacologia , Restrição Física , Estresse Fisiológico/efeitos dos fármacos , Estresse Fisiológico/fisiologia
13.
Stress ; 13(4): 343-54, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20536336

RESUMO

Visceral pain modulation by chronic stress in mice has been little studied. Electromyography (EMG) recording of abdominal muscle contractions, as a proxy to the visceromotor response (VMR), requires electrode implantation and post-surgical single housing (SH) which could affect the VMR to stress. To test this hypothesis, male mice had electrode implantation surgery (S) plus SH, or no surgery and were group housed (NS-GH) or single housed (NS-SH) and exposed to either water avoidance stress (WAS, 1 h/day) or left undisturbed in their home cages for 10 days. The VMR to phasic ascending colorectal distension (CRD) was assessed before (basal) and 24 h after 10 days of WAS or no stress using a surgery-free method of intraluminal colonic pressure (ICP) recording (solid-state manometry). WAS heightened significantly the VMR to CRD at 30, 45, and 60 mmHg in S-SH vs. NS-GH, but not compared to NS-SH conscious mice. Compared to basal CRD, WAS increased VMR at 60 mmHg in the S-SH group and decreased it at 30-60 mmHg in NS-GH mice, while having no effect in NS-SH mice. The average defecation during the hour of repeated WAS over 10 days was 1.9 and 2.4 fold greater in S-SH vs. NS-GH and NS-SH mice, respectively. These data indicate that the combination of S-SH required for VMR monitoring with EMG is an important component of repeated WAS-induced post-stress visceral hypersensitivity and defecation in mice.


Assuntos
Músculos Abdominais/fisiologia , Isolamento Social , Estresse Psicológico/fisiopatologia , Músculos Abdominais/efeitos dos fármacos , Músculos Abdominais/cirurgia , Animais , Atropina/farmacologia , Buprenorfina/farmacologia , Colo/fisiologia , Defecação , Dilatação Patológica/fisiopatologia , Eletrodos Implantados/efeitos adversos , Eletromiografia , Hiperalgesia/psicologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Dor , Limiar da Dor/fisiologia , Vísceras , Água
14.
Neurogastroenterol Motil ; 32(11): e13925, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32578346

RESUMO

BACKGROUND: Knowledge on optimal electrical stimulation (ES) modalities and region-specific functional effects of colonic neuromodulation is lacking. We aimed to map the regional colonic motility in response to ES of (a) the colonic tissue and (b) celiac branch of the abdominal vagus nerve (CBVN) in an anesthetized porcine model. METHODS: In male Yucatan pigs, direct ES (10 Hz, 2 ms, 15 mA) of proximal (pC), transverse (tC), or distal (dC) colon was done using planar flexible multi-electrode array panels and CBVN ES (2 Hz, 0.3-4 ms, 5 mA) using pulse train (PT), continuous (10 min), or square-wave (SW) modalities, with or without afferent nerve block (200 Hz, 0.1 ms, 2 mA). The regional luminal manometric changes were quantified as area under the curve of contractions (AUC) and luminal pressure maps generated. Contractions frequency power spectral analysis was performed. Contraction propagation was assessed using video animation of motility changes. KEY RESULTS: Direct colon ES caused visible local circular (pC, tC) or longitudinal (dC) muscle contractions and increased luminal pressure AUC in pC, tC, and dC (143.0 ± 40.7%, 135.8 ± 59.7%, and 142.0 ± 62%, respectively). The colon displayed prominent phasic pressure frequencies ranging from 1 to 12 cpm. Direct pC and tC ES increased the dominant contraction frequency band (1-6 cpm) power locally. Pulse train CBVN ES (2 Hz, 4 ms, 5 mA) triggered pancolonic contractions, reduced by concurrent afferent block. Colon contractions propagated both orally and aborally in short distances. CONCLUSION AND INFERENCES: In anesthetized pigs, the dominant contraction frequency band is 1-6 cpm. Direct colonic ES causes primarily local contractions. The CBVN ES-induced pancolonic contractions involve central neural network.


Assuntos
Colo/inervação , Estimulação Elétrica/métodos , Motilidade Gastrointestinal/fisiologia , Nervo Vago , Animais , Colo/fisiologia , Manometria , Sus scrofa , Suínos
15.
Endocrinology ; 150(1): 153-60, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18787020

RESUMO

Corticotropin-releasing factor (CRF) overexpressing (OE) mice are a genetic model that exhibits features of chronic stress. We investigated whether the adaptive feeding response to a hypocaloric challenge induced by food deprivation is impaired under conditions of chronic CRF overproduction. Food intake response to a 16-h overnight fast and ip injection of gut hormones regulating food intake were compared in CRF-OE and wild type (WT) littermate mice along with brain Fos expression, circulating ghrelin levels, and gastric emptying of a nonnutrient meal. CRF-OE mice injected ip with saline showed a 47 and 44% reduction of 30-min and 4-h cumulative food intake response to an overnight fast, respectively, compared with WT. However, the 30-min food intake decrease induced by ip cholecystokinin (3 microg/kg) and increase by ghrelin (300 microg/kg) were similar in CRF-OE and WT mice. Overnight fasting increased the plasma total ghrelin to similar levels in CRF-OE and WT mice, although CRF-OE mice had a 2-fold reduction of nonfasting ghrelin levels. The number of Fos-immunoreactive cells induced by fasting in the arcuate nucleus was reduced by 5.9-fold in CRF-OE compared with WT mice whereas no significant changes were observed in other hypothalamic nuclei. In contrast, fasted CRF-OE mice displayed a 5.6-fold increase in Fos-immunoreactive cell number in the dorsal motor nucleus of the vagus nerve and a 34% increase in 20-min gastric emptying. These findings indicate that sustained overproduction of hypothalamic CRF in mice interferes with fasting-induced activation of arcuate nucleus neurons and the related hyperphagic response.


Assuntos
Núcleo Arqueado do Hipotálamo/fisiologia , Hormônio Liberador da Corticotropina/genética , Ingestão de Alimentos/fisiologia , Ingestão de Energia , Jejum/fisiologia , Neurônios/fisiologia , Animais , Núcleo Arqueado do Hipotálamo/efeitos dos fármacos , Colecistocinina/farmacologia , Ingestão de Alimentos/efeitos dos fármacos , Ingestão de Energia/efeitos dos fármacos , Esvaziamento Gástrico/efeitos dos fármacos , Esvaziamento Gástrico/fisiologia , Regulação da Expressão Gênica , Genes fos , Grelina/farmacologia , Hiperfagia/fisiopatologia , Hipotálamo Médio/efeitos dos fármacos , Hipotálamo Médio/fisiologia , Camundongos , Nootrópicos/farmacologia , Sincalida/análogos & derivados , Sincalida/farmacologia
16.
Am J Physiol Gastrointest Liver Physiol ; 297(1): G215-27, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19407218

RESUMO

Corticotropin-releasing factor (CRF) 1 receptor (CRF(1)) activation in the brain is a core pathway orchestrating the stress response. Anatomical data also support the existence of CRF signaling components within the colon. We investigated the colonic response to intraperitoneal (ip) injection of cortagine, a newly developed selective CRF(1) peptide agonist. Colonic motor function and visceral motor response (VMR) were monitored by using a modified miniaturized pressure transducer catheter in adult conscious male Sprague-Dawley rats and C57Bl/6 mice. Colonic permeability was monitored by the Evans blue method and myenteric neurons activation by Fos immunohistochemistry. Compared with vehicle, cortagine (10 microg/kg ip) significantly decreased the distal colonic transit time by 45% without affecting gastric transit, increased distal and transverse colonic contractility by 35.6 and 66.2%, respectively, and induced a 7.1-fold increase in defecation and watery diarrhea in 50% of rats during the first hour postinjection whereas intracerebroventricular (icv) cortagine (3 microg/rat) had lesser effects. Intraperitoneal (ip) cortagine also increased colonic permeability, activated proximal and distal colonic myenteric neurons, and induced visceral hypersensitivity to a second set of phasic colorectal distention (CRD). The CRF antagonist astressin (10 mug/kg ip) abolished ip cortagine-induced hyperalgesia whereas injected icv it had no effect. In mice, cortagine (30 microg/kg ip) stimulated defecation by 7.8-fold, induced 60% incidence of diarrhea, and increased VMR to CRD. Stresslike colonic alterations induced by ip cortagine in rats and mice through restricted activation of peripheral CRF(1) receptors support a role for peripheral CRF(1) signaling as the local arm of the colonic response to stress.


Assuntos
Colo/inervação , Hormônio Liberador da Corticotropina/toxicidade , Motilidade Gastrointestinal/efeitos dos fármacos , Hiperalgesia/induzido quimicamente , Plexo Mientérico/efeitos dos fármacos , Receptores de Hormônio Liberador da Corticotropina/agonistas , Proteínas Recombinantes de Fusão/toxicidade , Estresse Psicológico/fisiopatologia , Animais , Hormônio Liberador da Corticotropina/administração & dosagem , Defecação/efeitos dos fármacos , Diarreia/induzido quimicamente , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Trânsito Gastrointestinal/efeitos dos fármacos , Hiperalgesia/metabolismo , Hiperalgesia/fisiopatologia , Hiperalgesia/prevenção & controle , Injeções Intraperitoneais , Injeções Intraventriculares , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Plexo Mientérico/metabolismo , Plexo Mientérico/fisiopatologia , Vias Neurais/efeitos dos fármacos , Vias Neurais/metabolismo , Vias Neurais/fisiopatologia , Medição da Dor , Fragmentos de Peptídeos/administração & dosagem , Permeabilidade , Estimulação Física , Pressão , Proteínas Proto-Oncogênicas c-fos/metabolismo , Ratos , Ratos Sprague-Dawley , Receptores de Hormônio Liberador da Corticotropina/metabolismo , Proteínas Recombinantes de Fusão/administração & dosagem , Estresse Psicológico/metabolismo
17.
Neurogastroenterol Motil ; 31(2): e13489, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30298965

RESUMO

BACKGROUND: Water avoidance stress (WAS) induces a naloxone-independent visceral analgesia in male rats under non-invasive conditions of monitoring. The objective of the study was to examine the role of brain CRF signaling in acute stress-induced visceral analgesia (SIVA). METHODS: Adult male Sprague-Dawley rats were chronically implanted with an intracerebroventricular (ICV) cannula. The visceromotor response (VMR) to graded phasic colorectal distension (CRD: 10, 20, 40, 60 mm Hg, 20 seconds, 4 minutes intervals) was monitored using manometry. The VMR to a first CRD (baseline) was recorded 5 minutes after an ICV saline injection, followed 1 hour later by ICV injection of either CRF (30, 100, or 300 ng and 1, 3, or 5 µg/rat) or saline and a second CRD, 5 minutes later. Receptor antagonists against CRF1 /CRF2 (astressin-B, 30 µg/rat), CRF2 (astressin2 -B, 10 µg/rat), oxytocin (tocinoic acid, 20 µg/rat), or vehicle were injected ICV 5 minutes before CRF (300 ng/rat, ICV) or 15 minutes before WAS (1 hour). KEY RESULTS: ICV CRF (100 and 300 ng) reduced the VMR to CRD at 60 mm Hg by -36.6% ± 6.8% and -48.7% ± 11.7%, respectively, vs baseline (P < 0.001), while other doses had no effect and IP CRF (10 µg/kg) induced visceral hyperalgesia. Astressin-B and tocinoic acid injected ICV induced hyperalgesia and prevented the analgesic effect of ICV CRF (300 ng/rat) and WAS, while astressin2 -B only blocked WAS-induced SIVA. CONCLUSIONS & INFERENCES: These data support a role for brain CRF signaling via CRF2 in SIVA in a model of WAS and CRD likely mediated by the activation of brain oxytocin pathway.


Assuntos
Encéfalo/metabolismo , Hormônio Liberador da Corticotropina/metabolismo , Estresse Psicológico/fisiopatologia , Dor Visceral/fisiopatologia , Animais , Hiperalgesia/fisiopatologia , Masculino , Ratos , Ratos Sprague-Dawley , Transdução de Sinais
18.
Curr Mol Pharmacol ; 11(1): 51-71, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-28240194

RESUMO

BACKGROUND: Corticotropin-releasing factor (CRF) pathways coordinate behavioral, endocrine, autonomic and visceral responses to stress. Convergent anatomical, molecular, pharmacological and functional experimental evidence supports a key role of brain CRF receptor (CRF-R) signaling in stress-related alterations of gastrointestinal functions. These include the inhibition of gastric acid secretion and gastric-small intestinal transit, stimulation of colonic enteric nervous system and secretorymotor function, increase intestinal permeability, and visceral hypersensitivity. Brain sites of CRF actions to alter gut motility encompass the paraventricular nucleus of the hypothalamus, locus coeruleus complex and the dorsal motor nucleus while those modulating visceral pain are localized in the hippocampus and central amygdala. Brain CRF actions are mediated through the autonomic nervous system (decreased gastric vagal and increased sacral parasympathetic and sympathetic activities). The activation of brain CRF-R2 subtype inhibits gastric motor function while CRF-R1 stimulates colonic secretomotor function and induces visceral hypersensitivity. CRF signaling is also located within the gut where CRF-R1 activates colonic myenteric neurons, mucosal cells secreting serotonin, mucus, prostaglandin E2, induces mast cell degranulation, enhances mucosal permeability and propulsive motor functions and induces visceral hyperalgesia in animals and humans. CRF-R1 antagonists prevent CRF- and stressrelated gut alterations in rodents while not influencing basal state. DISCUSSION: These preclinical studies contrast with the limited clinical positive outcome of CRF-R1 antagonists to alleviate stress-sensitive functional bowel diseases such as irritable bowel syndrome. CONCLUSION: The translational potential of CRF-R1 antagonists in gut diseases will require additional studies directed to novel anti-CRF therapies and the neurobiology of brain-gut interactions under chronic stress.


Assuntos
Encéfalo/metabolismo , Hormônio Liberador da Corticotropina/metabolismo , Trato Gastrointestinal/metabolismo , Transdução de Sinais , Animais , Trato Gastrointestinal/fisiopatologia , Humanos , Atividade Motora
19.
J Med Chem ; 50(7): 1668-74, 2007 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-17335188

RESUMO

The potencies and selectivity of peptide CRF antagonists is increased through structural constraints, suggesting that the resulting ligands assume distinct conformations when interacting with CRF1 and CRF2 receptors. To develop selective CRF receptor agonists, we have scanned the sequence -Gln-Ala-His-Ser-Asn-Arg- (residues 30-35 of [DPhe12,Nle21,38]Ac-hCRF4-41) with an i-(i+3) bridge consisting of the Glui-Xaa-Xbb-Lysi+3 scaffold, where residues i=30, 31, and 32. When i=31, stressin1-A, a potent CRF1 receptor-selective agonist was generated. In vitro, stressin1-A was equipotent to h/rCRF to release ACTH. Astressin1-A showed a low nanomolar affinity for CRF1 receptor (Ki=1.7 nM) and greater than 100-fold selectivity versus CRF2 receptor (Ki=222 nM). Stressin1-A released slightly less ACTH than oCRF in adult adrenal-intact male rats, with increased duration of action. Stressin1-A, injected intraperitoneally in rats, induced fecal pellet output (a CRF1 receptor-mediated response) and did not influence gastric emptying and blood pressure (CRF2 receptor-mediated responses).


Assuntos
Hormônio Liberador da Corticotropina/análogos & derivados , Peptídeos Cíclicos/síntese química , Receptores de Hormônio Liberador da Corticotropina/agonistas , Hormônio Adrenocorticotrópico/sangue , Animais , Pressão Sanguínea/efeitos dos fármacos , Células Cultivadas , Colo/efeitos dos fármacos , Colo/fisiologia , Hormônio Liberador da Corticotropina/síntese química , Hormônio Liberador da Corticotropina/química , Hormônio Liberador da Corticotropina/farmacologia , Defecação/efeitos dos fármacos , Esvaziamento Gástrico/efeitos dos fármacos , Trânsito Gastrointestinal/efeitos dos fármacos , Humanos , Masculino , Peptídeos Cíclicos/química , Peptídeos Cíclicos/farmacologia , Adeno-Hipófise/citologia , Ensaio Radioligante , Ratos , Ratos Sprague-Dawley , Relação Estrutura-Atividade
20.
Neuroreport ; 18(7): 679-82, 2007 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-17426598

RESUMO

Stress stimulates colonic motor function and plays a role in functional bowel disorders, prevalently in women. We examined, in conscious female rats, the influence of water avoidance stress for 60 min on colonic myenteric neuron activity using immunohistochemical detection of Fos as a marker of neuronal activity. In control rats, Fos immunoreactive nuclei were rare in proximal and distal colon and no defecation was observed. Water avoidance stimulated fecal pellet output, which was associated with Fos expression in myenteric ganglia of proximal and distal colon including in a population of peripheral choline acetyltransferase-immunoreactive neurons. Atropine blocked fecal pellet output but not Fos expression in myenteric ganglia. These results indicate that psychological stress stimulates the activity of colonic cholinergic myenteric neurons.


Assuntos
Colo/inervação , Motilidade Gastrointestinal/fisiologia , Plexo Mientérico/metabolismo , Estresse Psicológico/fisiopatologia , Animais , Feminino , Imuno-Histoquímica , Microscopia Confocal , Neurônios/metabolismo , Proteínas Proto-Oncogênicas c-fos/biossíntese , Ratos , Ratos Sprague-Dawley
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